2002 GTX RFI - Runs for 5 Seconds then Dies - Would Like to Hire a Specialist

[kdelcar1]

I have a 2002 GTX RFI that was running great then died instantly while running at about 30 mph. After towing it to shore, it would not restart. After a few days of sitting, it would start for 5 seconds then die. I have a copy of the official Sea Doo service manual and have conducted every diagnostic test I can find. Here is what I have found so far:

1. Getting good compression (155 psi/cylinder).
2. Good fuel flow (observed good fuel spray from the injectors while cranking after removing the fuel rail from the engine).
3. Hot spark (getting a hot 1/2 inch spark from each wire to the top of each plug during cranking)
4. Fuel pressure is showing 56 psi during cranking.
5. Measured 6 volts at each injector.
6. Checked resistances on all sensors and found them all to be within specs.
7. Battery is new. Voltage is above 12 volts.
8. Spark plugs are new and clean.
9. Checked all fuses at MPEM and rear electrical box. All are good.

The problem happened a couple months ago. Again, the engine was running great when it died suddenly (like someone turned off the key switch). After sitting for a couple days, the engine will run for about 5 seconds on the first crank. After that, it will not run at all on the second, third and fourth cranks, etc.

I'm going crazy trying to figure this out! I have talked with several specialists and they cannot figure it out either. Could it be the MPEM/ECU itself even though I am getting fuel and spark? Is there a way to check the MPEM/ECU before spending a lot of money on a new one? Is there a way to hire a specialist to help me through this problem? I'm willing to pay a consulting fee. Please provide any help you can.

Thanks,

Kevin

 

[kdelcar1]

I see that I have had 98 Views on this problem. No responses. Still unresolved. Symptoms are the same. Any ideas? Is there a way to hire a professional to give me advice? Thanks!

 

[racerxxx]

Here's probably the best thread to start with. You're going to need to get actual fuel pressures, not just a visual. Read the thread, perhaps something will stick out.

https://www.seadooforum.com/showthread.php?50814-The-RFI-(Rotax-Fuel-Injection-)-Spot

 

[kdelcar1]

Hi RacerXXX. Thanks for your feedback. As indicated in my first post, the actual measured fuel pressure is 56 psi. I'll see if I can figure out anything else in the post you provided. Thanks again. Other ideas would be appreciated.

 

[Coastiejoe]

Hi RacerXXX. Thanks for your feedback. As indicated in my first post, the actual measured fuel pressure is 56 psi. I'll see if I can figure out anything else in the post you provided. Thanks again. Other ideas would be appreciated.

Is that 56 psi while cranking by chance or just a "key on" pressure?

 

[kdelcar1]

56 psi was measured during cranking (not "key on" pressure). Is this significant?

 

[Coastiejoe]

56 psi was measured during cranking (not "key on" pressure). Is this significant?

I've seen it change cranking vs just key on. I was really more curious as compared to thinking of a great answer for you. If it is staying consistent while cranking, then that aspect of the system sounds good to me.

 

[Coastiejoe]

Ok, the only thing I can think you really need to look at is the Injectors. Getting 6 volts simply menas that voltage is getting to them. They are triggered by a ground, not a hot wire. You can SOMETIMES feel them working while cranking the engine. But the best way to test them is to get a NOID LAMP.

Buy one that has adjustable legs and you can use it for many engines, vehicles included. It will flash if the ground is being activated.

Further, you could pull the injector rail and see if fuel is actually passing through them. If you do this, just be safe as you will have an active spark happening within the engine (assuming you do in fact have spark?).

 

[Coastiejoe]

Does the 6v stay there when cranking?

 

[kdelcar1]

Hi Coastiejoe. As indicated in item #2 of my original post, I pulled the fuel rail and was able to watch a nice fuel spray coming from each injector. It appears that I am getting good fuel flow. When the fuel rail was attached, I was getting a constant 6 volts at each injector. I am also getting a hot spark as indicated in item #3 of my original post. Compression is also good as indicated in item #1 of my original post. Everything seems normal but it just won't run!

 

[Coastiejoe]

Hi Coastiejoe. As indicated in item #2 of my original post, I pulled the fuel rail and was able to watch a nice fuel spray coming from each injector. It appears that I am getting good fuel flow. When the fuel rail was attached, I was getting a constant 6 volts at each injector. I am also getting a hot spark as indicated in item #3 of my original post. Compression is also good as indicated in item #1 of my original post. Everything seems normal but it just won't run!

Ok, let's figure out what you are losing.

You'll want an inline fuel pressure tester and a noid lamp. Since it runs for 5 seconds, you'll see both items. Which do you lose?

 

[kdelcar1]

Hi CoastieJoe. When I had the fuel pressure gauge hooked up, It showed 56 psi when it ran for 5 seconds. Then, when I tried to start it again, it would only crank but not start. The fuel pressure gauge still showed 56 psi during cranking for ALL further starting attempts. The engine would not run, but I always recorded 56 psi on the fuel pressure gauge. It seems like fuel pressure is fine.

I'm not familiar with a Noid Light. What will this show me? Is it a fuel check or spark check? At this point, I am more suspicious of the electrical system then I am the fuel system, but who knows. Some people tell me that it may be the MPEM/ECU. When a MPEM/ECU goes bad, you can still get fuel and spark, but not at the correct time. When fuel or spark timing is off, the engine may not run. Any experience with this?

 

[mikidymac]

At this point it might be worth pulling the rotary valve cover and checking to make sure it is turning and the clearance is within spec since it looks like you have everything else needed to start. If either of these are not correct it will not start either.

 

[Coastiejoe]

Hi CoastieJoe. When I had the fuel pressure gauge hooked up, It showed 56 psi when it ran for 5 seconds. Then, when I tried to start it again, it would only crank but not start. The fuel pressure gauge still showed 56 psi during cranking for ALL further starting attempts. The engine would not run, but I always recorded 56 psi on the fuel pressure gauge. It seems like fuel pressure is fine.

I'm not familiar with a Noid Light. What will this show me? Is it a fuel check or spark check? At this point, I am more suspicious of the electrical system then I am the fuel system, but who knows. Some people tell me that it may be the MPEM/ECU. When a MPEM/ECU goes bad, you can still get fuel and spark, but not at the correct time. When fuel or spark timing is off, the engine may not run. Any experience with this?

The Noid lamp plugs into an injector harness plug. It will flash every time the injector is being told to work. If you're not losing fuel pressure you are either losing Spark and or fuel through the injector. The Noid lamp will stop flashing if something is killing the pulse to the injector.

 

[kdelcar1]

Hi Mikidymac! I was wondering about the Rotary Valve also. The reason I wasn't focusing on it is because I'm getting good compression on each cylinder - 155 psi on both. If the rotary valve was not turning, or if the clearances were bad, would I still get good compression? I don't see how I would get good compression when I have rotary valve problems, but maybe I'm missing something. Please provide your thoughts on this. Thanks!

 

[kdelcar1]

Hi Coastiejoe! Thanks for your explanation of the Noid lamp. I can see if I can find one and give a try. Again, with the fuel rail off, I observed a good fuel spray from each injector while cranking. I observed this about 10 ten times after cranking for a few seconds each time. Always a nice fuel spray coming from each injector. Would a Noid lamp tell me if the fuel timing is correct, or would it just tell me if a signal is getting to each injector?

Also, I consistently get a nice 1/2 inch spark jumping from each spark plug wire to the the top of each spark plug while cranking. I have tried this at least 10 times also to verify consistency. Nice hot spark every time. I'm suspicious however, of the spark timing. I have not verified that the spark is timed properly.

I would appreciate your further thoughts on these things. Thanks!

 

[Coastiejoe]

Hi Coastiejoe! Thanks for your explanation of the Noid lamp. I can see if I can find one and give a try. Again, with the fuel rail off, I observed a good fuel spray from each injector while cranking. I observed this about 10 ten times after cranking for a few seconds each time. Always a nice fuel spray coming from each injector. Would a Noid lamp tell me if the fuel timing is correct, or would it just tell me if a signal is getting to each injector?

Also, I consistently get a nice 1/2 inch spark jumping from each spark plug wire to the the top of each spark plug while cranking. I have tried this at least 10 times also to verify consistency. Nice hot spark every time. I'm suspicious however, of the spark timing. I have not verified that the spark is timed properly.

I would appreciate your further thoughts on these things. Thanks!

Bottom line, with spark fuel and compression it should run.

You say it runs for 5 seconds. Something MUST be getting dropped at the 5 second interval.

Timing can be an issue, but if it runs ok for 5 seconds I doubt that is the issue. If it never started or didn't run, then yes, there could be a timing concern.

If the FP pressure is at and stays at 56 psi, it is likely not the issue. But again, we need to see what is dropping out that is killing the engine.

I believe that there is an internal timer/relay within the MPEM. It provides everything needed while cranking but drops off once it starts and is fed from another source. If I am correct, the second feed could be your issue.

 

[kdelcar1]

Hi Coastiejoe. Thanks for your quick response! Your point on the Second Feed is very interesting! I have not heard this before. I think you may be on to something with this theory. I wanted to re-emphasize that it will only run for 5 seconds after it has been sitting for a day or two. This is very consistent. After sitting for a day or two it will always run for about 5 seconds on the first try. Then - all it will do is crank on each subsequent try on that particular day. No additional running on that day. Then - when I wait a day or two, it will run for 5 seconds on the first try again, then die. Subsequent attempts on that day result in cranking only, no running. Then I have to wait another day or two before it will run for 5 seconds again - and so on. Crazy!

If it is a Second Feed problem, how is this solved? Does it require a MPEM replacement? Is there a way to test the MPEM before spending a lot of money on a new one?

 

[Coastiejoe]

[MENTION=41828]Minnetonka4me[/MENTION] can provide much better info in regards to the MPEM.

 

[kdelcar1]

Thanks Coastiejoe. I already checked with Minnetonka4me (see my other post). He said that he cannot provide information that will help diagnose this problem. Thanks again!

Anyone else have experience with MPEM problems?

 

[ski-d00]

Have you tried a new voltage regulator? They can test fine but cause erratic problems and are a very common failure on the RFI and DIs.

 

[kdelcar1]

Hi Ski-d00: Yes, I replaced the voltage regulator. I have consistently been getting above 12 volts during cranking. The battery is new. Do you think a bad voltage regulator could cause the engine to die after 5 seconds?

 

[ski-d00]

Yes, failing voltage regulators can cause no start, sometimes start, cold start only, stall when hot issues, limp mode only, etc. issues. I've seen brand new ones not work right out of the box on more than one occasion. The 4tec voltage regulators seem to be more reliable on the DIs and RFIs, you just have to change the terminals.

MPEMs don't normally just fail out of the blue while running. They normally fail after somebody jump starts it from a running vehicle and even then they tend to blow fuses.
I suspect you are losing spark after 5 seconds, you can use an inductive timing light on the plug wire to check for signal. You can always put some fuel in the cylinders to make it run and squirt fuel through the throttle body to keep it running to rule out fuel issues.

 

[kdelcar1]

Thanks for the information sea-d00. Even after all the testing I've done, I still get a nice 1/2 inch hot spark jumping from each spark plug wire to the top of each plug when holding the wire close to the spark plugs with a screwdriver. I get this nice spark even when the engine won't run. Also, as mentioned in my previous posts, I have actually removed the fuel rail and watched a nice fuel spray coming from each injector when cranking the engine. After hooking the fuel rail back up the engine still does not run more that 5 seconds. I squirted some fuel through the throttle body and still nothing. I'm consistently getting 56 psi fuel pressure using a fuel pressure gauge when cranking. Also, I am consistently getting compression of 155 psi on each cylinder when cranking. Still only runs for 5 seconds then dies. Even with all this, I guess it could still be the voltage regulator. I'll see what I can find out. Let me know if you have any more ideas.

 

[kdelcar1]

Hi everyone! The problem is still not solved. The engine still runs for a few seconds then dies. I decided to post a YouTube video to show the results of 10 starting attempts. Here is the Youtube Link:

https://www.youtube.com/watch?v=P329Jrsf6vg

Here is a summary of what I have done so far:

1. Measured compression of 155 psi on each cylinder.
2. Observed good fuel spray from each injector while cranking after removing the fuel rail from the engine.
3. Getting a hot 1/2 inch spark from each spark plug wire to the top of each plug during cranking.
4. Measured 56 psi fuel pressure at the fuel rail during cranking.
5. Measured 6 volts at each injector.
6. Checked resistances on all sensors and found them all to be within specs.
7. Replaced battery and consistently measured above 12 volts.
8. Replaced spark plugs.
9. Checked all fuses at MPEM and rear electrical box and found them to all be good.
10. Changed out the MPEM/ECU with a known good one.
11. Replaced the voltage regulator.

I wanted to remind everyone of how the problem started. I was out cruising on the lake at about 30 mph when the engine died abruptly. The engine was running very smoothly with no missing or stuttering. Then, all of a sudden it just died instantly, like someone turned off the switch.

Please watch the video and let me know if you have any other ideas.

Thanks!

Kevin